Semiconductor substrate processing apparatuses are used for processing semiconductor substrates by techniques including, but not limited to, plasma etching, physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), plasma enhanced atomic layer deposition (PEALD), ion implantation, and resist removal. Semiconductor substrate processing apparatuses include gas delivery systems through which process gas is flowed and subsequently delivered into a processing region of a vacuum chamber of the apparatus by a gas distribution member such as a showerhead, gas injector, gas ring, or the like. For example, the gas delivery system can be configured to supply process gas to a gas injector positioned in the chamber above a semiconductor substrate so as to distribute process gas over a surface of the semiconductor substrate being processed in the chamber. Current gas delivery systems are constructed from many individual components, many of which have conduits therein through which process gas flows. The individual component interfaces require seals therebetween such that leaking does not occur when process gas is being supplied through the conduits of the assembled gas delivery system. Furthermore, many components of gas delivery system are formed from metal, such as stainless steel, wherein metal contaminants can be released from the process gas wetted surfaces forming the conduits of the component by corrosion, erosion and/or corrosion/erosion which may lead to contamination of semiconductor substrates during processing thereof. Thus, there is a need for gas delivery systems which comprise fewer individual components, and further, it is desired that the components thereof are corrosion, erosion, and corrosion/erosion resistant.